michaelmas exam Flashcards
Light Microscope
- they use a light source
- alive specimen
- uses lenses (objective and eyepiece)
- Lower magnification
- Magnification = 400= objective x eyepiece
- Lower resolution
- larger sub cellular structures
- cheaper
Electron microscope
- requires computers and lots of space
- Can only use dead samples
- fires electrons at the sample
- higher resolution
- higher magnification = 1,000,000
- very expensive
PLANT CELL
- chloroplasts
- cytoplasm
- cell wall
- cell membrane
- mitochondria
- nucleus
- vacuole
ANIMAL CELL
- cytoplasm
- Mitochondria
- Nucleus
- cell membrane
what are the differences between animal and plant cells
plant cells have vacuoles, cell walls and chloroplasts
what are eukaryotic cells
eukaryotic cells are cells that contain a nucleus
what are the 7 things living cells need/ do
movement respiration sensitivity growth reproduce excretion nutrient
what are the roles of the nucleus
- controls the activities of the cell
- contains deoxyreboneucleic acid
- The DNA is organised into chromosomes
what are the roles of the cell membrane
it controls the passage of substances into and out of the cell.
what is the role of the cytoplasm
its where most chemical reactions occur
Vacuoles
surrounded by a membrane
liquid called sap
vacuoles are permanent structures in plants
when do cells divide
cells divide when the body either need to grow, replace or repair damaged tissue. It also happens during asexual reproduction
where are chromosomes found
in the nucleus
what are chromosomes made from
chromosomes are made from DNA
how many chromosomes does the human body contain
the human body contains 23 chromosomes
how are new cells made
to make new cells the original cell has to divide this is called the cell cycle:
- DNA replicates to form 2 new copies. The cells grow grow and copies internal structures
- One set of chromosomes is pulled to each end of the cell. The nucleus also divides
- the cytoplasm and cell membrane divide into two identical cells
